.TH std::ranges::views::zip_transform,std::ranges::zip_transform_view 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::ranges::views::zip_transform,std::ranges::zip_transform_view \- std::ranges::views::zip_transform,std::ranges::zip_transform_view

.SH Synopsis
   Defined in header <ranges>
   template< std::move_constructible F, ranges::input_range... Views
   >

       requires (ranges::view<Views> && ...) && (sizeof...(Views) >
   0) &&
                 std::is_object_v<F> && std::regular_invocable<
                     F&, ranges::range_reference_t<Views>...> &&      \fB(1)\fP (since C++23)
                 /*can-reference*/<std::invoke_result_t<
                     F&, ranges::range_reference_t<Views>...>>
   class zip_transform_view

        : public ranges::view_interface<zip_transform_view<F,
   Views...>>
   namespace views {

       inline constexpr /*unspecified*/ zip_transform =               \fB(2)\fP (since C++23)
   /*unspecified*/;

   }
   Call signature
   template< class F, ranges::viewable_range... Rs >

       requires /* see below */                                           (since C++23)

   constexpr auto zip_transform( F&& f, Rs&&... rs );

   1) zip_transform_view is a range adaptor that takes an invocable object and one or
   more views, and produces a view whose i^th element is the result of applying the
   invocable object to the i^th elements of all views.
   A type T models the exposition-only concept /*can-reference*/ if and only if T& is a
   valid type.
   2) views::zip_transform is a customization point object.

   When calling with one argument f, let FD be std::decay_t<decltype(f)>, if:

     * FD models copy_constructible,
     * FD& models regular_invocable, and
     * std::invoke_result_t<FD&> is an object type,

   then views::zip_transform(f) is expression-equivalent to ((void)f,
   auto(views::empty<std::decay_t<std::invoke_result_t<FD&>>>)). Otherwise, the call to
   views::zip_transform is ill-formed.

   When calling with more than one arguments f and rs..., views::zip_transform(f,
   rs...) is expression-equivalent to ranges::zip_transform_view(f, rs...).

   zip_transform_view models the concepts random_access_range, bidirectional_range,
   forward_range, input_range, common_range, and sized_range when the underlying
   ranges::zip_view<Views...> models respective concepts.

.SH Member functions

   constructor   constructs a zip_transform_view
   (C++23)       \fI(public member function)\fP
   begin         returns an iterator to the beginning
   (C++23)       \fI(public member function)\fP
   end           returns an iterator or a sentinel to the end
   (C++23)       \fI(public member function)\fP
   size          returns the number of elements. Provided only if each underlying
   (C++23)       (adapted) range satisfies sized_range.
                 \fI(public member function)\fP
         Inherited from std::ranges::view_interface
   empty         returns whether the derived view is empty. Provided if it satisfies
   (C++20)       sized_range or forward_range.
                 \fI(public member function of std::ranges::view_interface<D>)\fP
   cbegin        returns a constant iterator to the beginning of the range.
   (C++23)       \fI(public member function of std::ranges::view_interface<D>)\fP
   cend          returns a sentinel for the constant iterator of the range.
   (C++23)       \fI(public member function of std::ranges::view_interface<D>)\fP
   operator bool returns whether the derived view is not empty. Provided if
   (C++20)       ranges::empty is applicable to it.
                 \fI(public member function of std::ranges::view_interface<D>)\fP
   front         returns the first element in the derived view. Provided if it
   (C++20)       satisfies forward_range.
                 \fI(public member function of std::ranges::view_interface<D>)\fP
   back          returns the last element in the derived view. Provided if it satisfies
   (C++20)       bidirectional_range and common_range.
                 \fI(public member function of std::ranges::view_interface<D>)\fP
   operator[]    returns the n^th element in the derived view. Provided if it satisfies
   (C++20)       random_access_range.
                 \fI(public member function of std::ranges::view_interface<D>)\fP

   Deduction guides

.SH Member types

   Member type         Definition
   InnerView (private) ranges::zip_view<Views...>.
                       (exposition-only member type*)
                         * ranges::iterator_t<const InnerView> if Const is true,
   ziperator (private)     otherwise
                         * ranges::iterator_t<InnerView>.
                           (exposition-only member type*)
                         * ranges::sentinel_t<const InnerView> if Const is true,
   zentinel (private)      otherwise
                         * ranges::sentinel_t<InnerView>.
                           (exposition-only member type*)

   Data members

   Member object  Definition
   zip_ (private) An underlying view object of type InnerView
                  (exposition-only member object*)
   fun_ (private) A wrapped invocable object of type movable-box<F>
                  (exposition-only member object*)

   Nested classes

   iterator the iterator type
   (C++23)  (exposition-only member class template*)
   sentinel the sentinel type used when the underlying zip_view is not a common_range
   (C++23)  (exposition-only member class template*)

.SH Notes

    Feature-test macro   Value    Std                 Feature
                                        std::ranges::zip_view,
   __cpp_lib_ranges_zip 202110L (C++23) std::ranges::zip_transform_view,
                                        std::ranges::adjacent_view,
                                        std::ranges::adjacent_transform_view

.SH Example


// Run this code

 #include <array>
 #include <iostream>
 #include <list>
 #include <ranges>
 #include <vector>

 void print(auto const rem, auto const& r)
 {
     std::cout << rem << '{';
     for (char o[]{0,' ',0}; auto const& e : r)
         std::cout << o << e, *o = ',';
     std::cout << "}\\n";
 }

 int main()
 {
     auto v1 = std::vector<float>{1, 2, 3};
     auto v2 = std::list<short>{1, 2, 3, 4};
     auto v3 = std::to_array({1, 2, 3, 4, 5});

     auto add = [](auto a, auto b, auto c) { return a + b + c; };

     auto sum = std::views::zip_transform(add, v1, v2, v3);

     print("v1:  ", v1);
     print("v2:  ", v2);
     print("v3:  ", v3);
     print("sum: ", sum);
 }

.SH Output:

 v1:  {1, 2, 3}
 v2:  {1, 2, 3, 4}
 v3:  {1, 2, 3, 4, 5}
 sum: {3, 6, 9}

.SH See also

   ranges::zip_view       a view consisting of tuples of references to corresponding
   views::zip             elements of the adapted views
   (C++23)                \fI(class template)\fP (customization point object)
   ranges::transform_view a view of a sequence that applies a transformation function
   views::transform       to each element
   (C++20)                \fI(class template)\fP (range adaptor object)
   ranges::elements_view  takes a view consisting of tuple-like values and a number N
   views::elements        and produces a view of N^th element of each tuple
   (C++20)                \fI(class template)\fP (range adaptor object)
